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radio becomes noisy when airborne

henriquerv9

henriquerv9

Active Member
GOOD MORNING,

I HAVE AN ICA200 IN MY -7, AND THE RADIO IS WORKING PERFECT WHILE THE AIRCRAFT IS ON THE GROUND AND TAXING (LEVEL SIGNAL/QUALITY 5/5). AS SOON AS I GET AIRBORN THE SIGNAL QUALITY DROPS SIGNIFICANTLY TO 3/5 WHILE TRANSMITTING (LOTS OF NOISE REPORTED FROM THE CONTROLLER, BUT I HEAR THEM WELL). WHEN I LAND BACK THE SIGNAL INSTANTLY GETS BETTER AGAIN. BUT I ALSO HAD TO OPEN THE PM1000 SQUELCH ALMOST FULL TO NOT GET NOISE THROUGH IT. IF I TURN THE PM100 OFF, I STOPPED LISTEN THE NOISE, BUT THE CONTROLLER STILL REPORT LOW SIGNAL QUALITY WHILE I HEAR THEM LOUD AND CLEAR.

HAS ANYONE EXPERIENCED SIMILAR PROBLEMS? ANY IDEA WHAT COULD BE HAPPENING?

HENRIQUE CASTRO
 
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What type of ignition do you have?

I just learned that auto plugs with more than 100 hours +/- can impact the transmission quality of the ICA200.
 
Do a full-power runup on the ground and transmit while at power. If it comes in noisy, suspect the ignition or plugs. If it's a clean transmission, I would suspect constructive reflecting ground plane interference and change the position of the antenna.

When in flight at idle power, what is the signal quality?
 
everything is aircraft parts.
engine is a Mattituck lycoming IO360, all parts related is from vans FF kit. Aircraft is 32 TTSN... :)
 
When flying at 1500rpm is still noisy. a little bit less, but still noisy. Maybe has something to do with the radio grounding location?
 
If it's cleaner at low rpm, I would suspect ignition noise. Try as low an rpm as you can accomplish (full idle, best glide speed) and see what that yields for signal.

If you're brave, go true "engine-out" from altitude and kill the mags for a radio check. That will tell you for sure if it's ignition noise.
 
Another idea

Ignition noise is certainly a possibility, but...

...The A200 is a great, low cost radio. That said, the factory settings for mic gain and side tone are set way too high for the high noise environment of the RV. With the mic gain too high, the mic picks up ambient noise and it comes across as a bad transmission. Try adjusting both gain and side tone down and see what happens. These adjustments are made using potts that are accessed from the top of the radio (you need to slide it out of the radio tray.)

Start by adjusting the mic gain so that your transmissions sound good to the controller, then adjust the side tone so that you sound good to yourself.

Some trial and error is required, but you can fine tune it into a much better-performing radio. Best part is, this fix is zero cost. Try it.
 
sprucemoose said:
Start by adjusting the mic gain so that your transmissions sound good to the controller, then adjust the side tone so that you sound good to yourself.

Some trial and error is required, but you can fine tune it into a much better-performing radio. Best part is, this fix is zero cost. Try it.
Click to expand...

Jeff is right on with this. Also consider ordering this from Oregon Aero. This product will go a long way to correcting your problem and I have them on my headsets. Good luck.

Edit... When Oregon Aero shipped mine they could have been shipped in a letter envelope since the covers are light and small, but they shipped in a box and I got nicked pretty heavy for the shipping. The purpose of the box? To send me a heavy catalog of their products. Let them know that you don't want to pay $7 for shipping to get a catalog, unless you want it of course.
 
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My problem was arcing in ignition system

I had a problem with static while flying that was getting progressively worse. I switched off the mags one at a time, and sure enough one was the main culprit.

I've got EMAG/PMAG and auto plugs

I pulled every ignition plug and hosed it out with WD40 real good. A surprising amount of black stuff, which I assume to be carbon, came out of several.

This solved the problem, but it seemed to be gradually coming back so I added this procedure to my oils change maintenance schedule.

I'm also going to be sure the connectors are not sprung open too wide.
 
I bet a nickel it's mic gain

I had a similar-sounding problem with my brand new Icom radio and RV-6A. Everything worked on the ground, but when I keyed the mic in flight, the feedback almost blew my ears off.

Pull the radio out, peel back the foil covering the access hole in the top panel for mic gain. From the factory, mine was set about the middle. I turned it down to about 20-25% (1/4 of clockwise travel) before I had good feedback to my ears as well as easy voice activation of triggering the mic.

If you remove your headphones in cruise flight, you'll see what a noisy environment the RV cockpit is. Decrease sensitivity of the mic and I bet your problem goes away. The other good news, it is the simplest thing to try. I tried about 6 other things to no avail before I found this. I hope it works for you.
 
radio becomes noisy when airborne - PROBLEM SOLVED

Hi all,

Just a feedback for the post. The problem is really the mic gain adjustment on the icom. I took the icom out, set the pot to about 20% of its course (it came from factory about 50% in my case) and now its just smooth as should be.

Thanks for all information guys!

henrique castro
RV7 - 50 hours on hobbs....
 
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